Hydroquinone is a strong inhibitor of melanin production that has long been established as the most effective ingredient for reducing and potentially eliminating melasma (Source:
Journal of Dermatological Science, August, 2001, Supplemental, pages 68–75). In different concentrations it inhibits or prevents skin from making the substance responsible for skin color. Hydroquinone does not bleach the skin, which is why calling it a “bleaching agent” is a misnomer; it can’t remove pigment from the skin cell. But blocking the skin’s ability to synthesize melanin absolutely can reduce and eliminate the brown discolorations, whether they are caused by sun damage or hormonal influences. Over-the-counter hydroquinone products can contain 0.5% to 2% concentrations
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Yet research indicates skin reactions are rare and minor, or a result of using extremely high concentrations of hydroquinone, or of using hydroquinone products that have been adulterated with dangerous ingredients.
Hydroquinone-based products were banned in South Africa years ago where problems were most frequently seen. However, hydroquinone products in South Africa and other countries are notorious for containing mercury and glucocorticoids, among other caustic and illegal contaminants, which were believed by many to be the cause of the disorders experienced (Sources: International Journal of Dermatology, February 2005, pages 112–115; and British Journal of Dermatology, March 2003, pages 493–500).
There is abundant research showing hydroquinone to be safe and extremely effective.
(Sources: Cutis, April 2008, pages 356–371 and August 2006, pages S6–S19; Journal of
Cosmetic Laser Therapy, September 2006, pages 121–127; American Journal of Clinical Dermatology,
July 2006, pages 223–230; and Journal of the American Academy of Dermatology,
May 2006, pages
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This has been shown to have better efficacy than peels, but although cryotherapy was more likely to produce substantial lightening it was more painful and took more time to heal. (Source: Journal of the European Academy of Dermatology and Venereology, March
2008, pages 316–319.)
Kojic Acid
A by-product of the fermentation process of malting rice for use in the manufacture of sake, Japanese rice wine, kojic acid definitely has convincing research, both in vitro and in vivo and in animal studies, showing that it is effective for inhibiting melanin production.
(Sources: Cellular Signaling, September 2002, pages 779–785; Biological and Pharmaceutical
Bulletin, August 2002, pages 1045–1048; Analytical Biochemistry, June 2002, pages 260–268;
American Journal of Clinical Dermatology, September–October 2000, pages 261–268; and
Archives of Pharmacal Research, August 2001, pages 307–311.)
However, kojic acid in concentrations high enough to make a difference can be irritating, and far more irritating than the more effective hydroquinone. (Source: Skin Lightening and
Depigmenting Agents, emedicine.com, July 2008.)
SOLUTIONS FOR SKIN LIGHTENING 171
So why don’t more products claiming to lighten skin contain kojic acid? Kojic acid is